1. Field of the Invention
This invention relates to a door system with draught eliminating effect for use in an entrance/exit of a building.
2. Description of the Related Art
Heretofore, there is known an automatic sliding door provided at an entrance/exit of a building such as office buildings and public buildings. Such an automatic sliding door is provided to keep an air-conditioned state inside the building and/or to prevent draught from coming inside the building.
In the conventional automatic door system, for example, a box shaped compartment is defined in an entrance zone of a building, an entrance and an exit are defined in positions opposing to each other of the compartment, and a pair of automatic sliding doors are provided on the entrance and the exit, respectively. Each of the automatic doors is individually controlled in such a manner that the door is opened each time a passerby passes the compartment.
In the above-constructed automatic door system, a certain draught eliminating effect is secured by the compartment. However, in a case that a passerby is about to come into the compartment through the entrance door (exit door), and almost at the same timing, another passerby who is on the way of passing the compartment is about to go out of the compartment through the exit door (entrance door), or traffic of passersby through the compartment is heavy, it is highly likely that a situation where both of the entrance door and the exit door are opened may occur. Thus, the conventional automatic door system fails to accomplish complete draught eliminating effect.
Furthermore, in the above arrangement, since each of the automatic doors is individually opened and closed, two driving sources are needed. This may raise the production cost and running cost of the door system.
There is also known another type of door system, namely, a revolving door. A revolving door is operated in such a manner that a plurality of door panels are rotated around a central rotating element in a fixed direction. Such a revolving door system provides more secured draught eliminating effect than the automatic sliding door system because there are defined a certain number of small sections by the door panels. However, the revolving door system requires a relatively large space and requires signal communication between the door panels by slip rings, which raises the production cost and running cost of the door system.